Such containers have a head portion, an outer wall and two injection-molded partial shells. Each of the shells has an external handle with handle roots, a recessed grip located between the handle roots and a wall region having an outer surface which follows the contour of the three-handled container in the regions of the handle roots, the outer wall, the recessed grip, and the head portion. Both partial shells are of a form that is essentially symmetrical to the central parting line of the container and are arranged essentially symmetrically to the central parting line, and blown plastic extends between the partial shells.
A container as described is disclosed in the German Patent No. 21 51 913. A device for its manufacture is disclosed in the German Patent Specification No. 19 27 014. A three-handled container naturally has three handles so that when they are empty two external handles of neighboring containers can be grasped with one hand and thus four container can be carried in all. If the container is full, it is carried by the central handle.
The weights of containers of this type including contents may be considerable. The standard three-handled container holds 20 liters. There are, however, also 30-liter containers. The external handles of conventional containers comprise injection molded material. It is known that injection-molded components, although having the same base material, are essentially more rigid than blown components and are also much smoother, this being due to a difference in the pressure of production greater than a factor of 100. They are thus of high quality where stress characteristics and carrying characteristics are concerned. The central handle, however, has an essentially rougher surface. If may be that this is of little importance if a container is carried occasionally. If, however, many containers must be carried, as is necessary for example when supplying the population during disasters or when for example the tanks of an aircraft which contain many cubic meters have to be filled from containers, the difference between a small and a high degree of surface roughness is very quickly noticeable and it is also very quickly noticed whether flashes are present or not.
As the central handle is made from the same parison material which the extruder extrudes, only the duubled material thickness of this parison is available as a volume for producing the central handle. This means that the central handle remains realtively narrow, so that it cuts into the hand during carrying. Thus success has not yet been had in the case of plastic containers, with what has been known since the 1940's with metallic three-handled container: namely, making the central handle wider and easy to carry and particularly with a low degree of surface roughness and without substantial flashes.
In the case of plastic containers, the central handle had also to be kept substantially shorter since it is made from less rigid material. Thus no success has been had with making this handle as long as has been the case with metal containers for a long time.
Moreover, the central handle is situated at a lower level than the two external handles. This is done because it is not particularly capable of withstanding stresses for example if dropped or stacked. This means that it is difficult for a large human fist to fit into the space between the central handle and the adjacent upper side of the container, and impossible when a glove is worn. The central handle must also be located lower down for a reason--which is not apparent from the publications--which is because the two handle roots must be pinched. The tool for pinching, however, requires space.
As is also show in the Figure of German Patent Specification No. 19 27 014, a multicomponent tool is necessary because of the numerous undercuts. This requires expenditure on the production machine, on synchronization, and so on.